Pharmacokinetics of metformin in collagen-induced arthritis rats

Integration of tissue distribution, PK-PD modeling and metabolomics reveals inflammatory-immune response alterations in Gaultheria leucocarpa var. yunnanensis alleviating rheumatoid arthritis

ETHNOPHARMACOLOGICAL RELEVANCE

Gaultheria leucocarpa var. yunnanensis, a distinguished member of the Gaultheria Kalm ex L. in the Ericaceae family, has been traditionally employed in the southwestern regions of China for the efficacious treatment of rheumatoid arthritis (RA). The anti-RA fraction (ARF) derived from Gaultheria leucocarpa var. yunnanensis has been previously demonstrated to effectively alleviate RA in vivo and in vitro.

AIM OF THE STUDY

This research endeavor is dedicated to surveying the pharmacokinetic (PK) processes of ARF within plasma and tissues, profiling its metabolites in vivo, discerning the material foundation of its therapeutic efficacy, and delineating its anti-RA mechanisms.

MATERIALS AND METHODS

The prototype components and metabolites of ARF in plasma and seven tissues of RA rats were analyzed by LC-MSn. Advanced LC-MS/MS and HPLC-DAD methodologies were developed to investigate the plasma PK profiles and tissue distribution characteristics of MSTG-A, MSTG-B, and Gaultherin in both RA model rats and healthy controls. A panel of four cytokines (TNF-α, IL-1, IL-6, and IL-2) was selected as pharmacodynamic (PD) biomarkers and quantified using ELISA. The PK, PD, and PK-PD modeling of ARF were skillfully constructed by combining WinNonlin with Matlab software, enabling a comprehensive analysis of the interrelationships between components and effect markers. A non-targeted plasma metabolomics approach employing LC-QE-MS was utilized to insight into the underlying mechanisms of ARF alleviating RA.

RESULTS

The quantity and diversity of identified prototypical components and metabolites of ARF in model rat plasma increased over time. The spleen exhibited the highest number of metabolites and prototypical compounds of ARF. The UPLC-QQQ-MS/MS and HPLC-DAD method were developed and validated for the quantification of three chemical markers in rat plasma and tissues, respectively. Three effective components (MSTG-B, MSTG-A, and Gautherin) demonstrated linear dynamics in plasma and tissues at an oral dosage of 3 g/kg ARF. The PK-PD models involving three components and four inflammatory cytokines aligned with the one company model, demonstrating a linear correlation through compartmental modeling and curve fitting analysis. Significant variations were identified in the concentrations of various amino acids and lipid metabolites among the CON, ARF, and MTX groups in comparison to the MOD group, which are intricately linked to the inflammation-immunity response.

CONCLUSIONS

The three components displayed favorable bioavailability and were rapidly eliminated in RA rats, collectively exerting an anti-RA effect. The mechanism by which ARF mitigates RA is associated with the modulation of inflammation-immunity related metabolic pathways. The spleen may serve as the target tissue for ARF attenuating RA. These findings provide a robust foundation for rationalizing intervention strategies, elucidating biological mechanisms, and advancing the clinical application of ARF in the amelioration of RA.

The intestinal absorption of triptolide for the treatment of rheumatoid arthritis is mediated by transporters

Tripterygium wilfordii Hook. f. is a traditional Chinese herb that is used to treat rheumatoid arthritis (RA). Triptolide (TP), an epoxidized diterpene lactone extracted from this herb, has been suggested to be the primary active and toxic component. In this work, the material basis and molecular mechanism of toxicity induced by T. wilfordii preparations in RA were investigated. Female rats with collagen-induced arthritis were given 500 μg·kg-1 TP intragastrically or intravenously. Compared with that in the control group, the AUClast in the CIA group was 1.7-fold greater after intragastric administration, while this value decreased 22.6 % after intravenous administration, suggesting that the absorption of TP was significantly greater in the CIA group. The results from RT-PCR and probe substrate perfusion indicated that Oatp1a5 expression was upregulated while P-glycoprotein (P-gp) expression was downregulated in the duodenums of CIA rats. Naringin, an inhibitor of Oatp1a5, decreased the Peff of TP in the rat duodenum by 27.9 %, whereas verapamil hydrochloride, an inhibitor of P-gp, increased the Peff by 50.8 %, suggesting that Oatp1a5 and P-gp mediate the uptake and efflux of TP in the rat duodenum, respectively. Furthermore, among the upstream nuclear receptors, the mRNA expression levels and protein expression levels of FXR and VDR were noticeably decreased. In the present study, the absorption of TP in the duodenums of CIA rats significantly increased due to the upregulation of Oatp1a5 expression and the downregulation of P-gp expression, leading to an increase in TP plasma exposure after intragastric administration. The altered expression of Oatp1a5 and P-gp may be related to FXR and VDR.

Bidirectional pharmacokinetic drug interactions between olaparib and metformin

OBJECTIVE

Olaparib is a PARP (poly-ADP-ribose polymerase) inhibitor used for maintenance therapy in BRCA-mutated cancers. Metformin is a first-choice drug used in the treatment of type 2 diabetes. Both drugs are commonly co-administered to oncologic patients with add-on type 2 diabetes mellitus. Olaparib is metabolized by the CYP3A4 enzyme, which may be inhibited by metformin through the Pregnane X Receptor. In vitro studies have shown that olaparib inhibits the following metformin transporters: OCT1, MATE1, and MATE2K. The aim of the study was to assess the influence of 'the perpetrator drug' on the pharmacokinetic (PK) parameters of 'the victim drug' after a single dose. To evaluate the effect, the AUC0→∞ (area under the curve) ratio was determined (the ratio between AUC0→∞ in the presence of the perpetrator and AUC0→∞ without the presence of the perpetrator).

METHODS

Male Wistar rats were assigned to three groups (eight animals in each group), which were orally administered: metformin and olaparib (IMET+OLA), vehiculum with metformin (IIMET), and vehiculum with olaparib (IIIOLA). Blood samples were collected after 24 h. HPLC was applied to measure the concentrations of olaparib and metformin. The PK parameters were calculated in a non-compartmental model.

RESULTS

Metformin did not affect the olaparib PK parameters. The AUC0→∞ IMET+OLA/IIIOLA ratio was 0.99. Olaparib significantly increased the metformin Cmax (by 177.8%), AUC0→t (by 159.8%), and AUC0→∞ (by 74.1%). The AUC0→∞ IMET+OLA/IIMET ratio was 1.74.

CONCLUSIONS

A single dose of metformin did not affect the PK parameters of olaparib, nor did it inhibit the olaparib metabolism, but olaparib significantly changed the metformin pharmacokinetics, which may be of clinical importance.

How to Model Rheumatoid Arthritis in Animals: From Rodents to Non-Human Primates

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease influenced by both genetic and environmental factors. At present, rodent models are primarily used to study the pathogenesis and treatment of RA. However, the genetic divergences between rodents and humans determine differences in the development of RA, which makes it necessary to explore the establishment of new models. Compared to rodents, non-human primates (NHPs) are much more closely related to humans in terms of the immune system, metabolic conditions, and genetic make-up. NHPs model provides a powerful tool to study the development of RA and potential complications, as well as preclinical studies in drug development. This review provides a brief overview of the RA animal models, emphasizes the replication methods, pros and cons, as well as evaluates the validity of the rodent and NHPs models.